Study On Water-based Fracturing Fluids Damage Of Changqing Reservoir

Chanqing oil field is the classic of low permeability reservoirs; generally need to take fracturing measure to be able to obtain a higher output. The quality of fracturing fluids is very important in fracturing, the research on fracturing fluid damage mechanism and the improvement of fracturing fluids performance is the project which the people devote to studying.The NMR core sample analysis technology can be used to measure oil and water saturation, the constrained fluid and free fluid degree in core. Therefore, by using this technology and the conventional experimental technology, it is possible to quantitatively evaluate reservoir damage mechanism respectively by fracturing fluids.This article mainly study the damage of core permeability by the filtrate viscosity after gel break, small and macro-molecule matter resorted, as well as water locking effect, clay inflated by absorbing water. The different damage rate about different depth of rock permeability has also done. The main damage mechanism and damage degree by fracturing fluids has carried on the analysis.The research indicated that: After fracturing fluids pushed in the core sample, damage rate of core sample by clay inflated by absorbing water and the water locking effect all about 10%; the main damage mechanism is the macro-molecule matter adsorbed and detained in the core sample, injury rate is 20%-30%. The viscosity of fracturing fluids is lower, damage degree is higher, the molecular weight of gelatinizer...